The present invention relates in general to an extruder screw, and in particular to an extruder screw of a type having a front end and formed therein a temperature-control bore extending to the front end for supply and drainage of free-flowing temperature-control fluid, and a screw tip threadably engaging the front end of the extruder screw at interposition of at least one seal for sealing off the forwardly open temperature-control bore.
In conventional extruder screws of this type, the screw tips to be attached to the front end of the extruder screw are provided on the tip-distal end with a thread and with a cylindrical part which is formed with ring grooves for receiving O rings. Only small forces can be applied via frictional engagement on the cylindrical area of the screw tip to threadably engage such screw tips. Furthermore, the cylindrical areas between screw part and screw tip must be made at high precision in order to assure the required sealing action of the O rings arranged in the cylindrical part.